Breast pump



FIG. 1 is a front elevational view of a breast pump, showing my new design;

FIG. 2 is a right side elevational view thereof, the left side elevational view being a mirror image thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is an exploded side elevational view thereof; and

FIG. 5 is a right side, rear perspective view thereof. 

The ornamental design for a breast pump, as shown and described. 